code: def variance(x):
      avgx = average(x)
      return list(map(lambda y: (y - avgx) ** 2, x))
  
file_path: backtrader/samples/sratio/sratio.py
imports: from __future__ import absolute_import, division, print_function, unicode_literals
  import argparse
  import itertools
  import math
  import operator
  import sys
label_desc: Use image node_id 2 for calling a global function with example usage: variance(x) and returns: list